Help with MQL5 Arbitration

In my first job here on MQL5 for $120, the work took me more than 10 days to complete. It fulfills 100% of the tasks and specifications of the technical task. When delivering the EX5 or preliminary version, the client reviewed it and tells me that the EA is not profitable at all, that it's not what he was looking for. Is it my fault? How can I defend myself in arbitration? He claims that it's not what he expected. I fulfilled the technical task to the letter.

Should I send the source code? What does the arbitration team analyze? The source code? It should be noted that the source code was not provided because the preliminary version was sent first.

I await your messages and your help. Someone who knows or has won arbitrations, tell me how I can win it. I am 100% sure that my work fulfills the technical task.